Buckle

ABSTRACT

A buckle  1  comprises a male member  10  and a female member  20  for receiving and anchoring the male member. The male member  10  has a male member main body  11,  a resiliently deformable insertion piece  15  formed on the male member main body, an anchor surface  18  formed on the insertion piece and an operating section  17  also formed on the insertion piece and adapted to resiliently deform the insertion piece. The female member  20  has a female member main body  21,  an insertion hole  23  formed in the female member main body and adapted to receive the corresponding insertion piece of the male member inserted into it, anchor-holding surface  27  to be engaged with the anchor surface of the male member so as to hold the male member in the female member and an aperture  25  adapted to expose the operating section of the male member to the outside as the anchor-holding surface is engaged with the anchor surface. The aperture is formed by inwardly cutting out the front and rear walls  21 B,  21 C of the periphery of the female member main body  21  having the insertion hole from the lateral wall  21 A of the main body and provided at peripheral edge  26 B thereof with projecting section  28  projecting toward the aperture.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a buckle having a male member and a female member, more particularly, to a buckle to be used for connecting and disconnecting the opposite ends of a single strap of a pair of straps.

[0003] 2. Description of Related Art

[0004] Buckles are being used as means for connecting and disconnecting the opposite ends of a single strap of a pair of straps.

[0005] A buckle conventionally comprises a plug and socket into which the plug is inserted and by which it is held. The plug is provided with a plug main body and a pair of insertion pieces arranged in parallel with each other at the respective lateral sides of the plug main body. On each of the insertion pieces, an insertion guide surface is formed at the front part thereof while an operating section and an anchor surface are formed at respective positions closer to the base section of the insertion piece than the insertion guide surface. The socket comprises a socket main body and an insertion hole that is cut through the socket main body and into which the plug is inserted. Abutting sections are formed respectively on the lateral walls of and near the insertion hole and adapted to resiliently deform the corresponding respective insertion pieces in (inward) directions that are substantially perpendicular to the direction along which the insertion pieces are inserted as the latter abuts the respective insertion guide surfaces of the plug. At the same time, an anchor-holding surface for holding the anchor surface and an aperture for exposing the operating section of the insertion piece are respectively formed on each lateral wall in area located beyond the respective abutting section as viewed from the insertion hole.

[0006] With the above described arrangement, to anchor the plug to the socket, the user inserts the insertion pieces of the plug into the insertion hole of the socket. Then, the insertion guide surfaces formed at the front ends of the insertion pieces respectively abuts the corresponding abutting sections of the socket and hence, as the insertion pieces are inserted further, they are resiliently deformed toward the inside as viewed from the lateral walls of the insertion hole. When the anchor surfaces of the insertion pieces go beyond the respective anchor-holding surfaces formed in the socket, the anchor surfaces of the insertion pieces that have been resiliently deformed toward the inside restore the original profile as they turned back respectively toward the outsides and consequently the anchor surfaces of the insertion pieces are held by the respective anchor-holding surfaces formed on the socket. In this state, the operating sections of the plug are exposed to the outside through the respective apertures of the socket.

[0007] To release the plug from the socket, the user depresses the operating sections exposed to the outside through the respective apertures of the socket toward the inside typically by means of the thumb and one of the fingers to resiliently deform the insertion pieces toward the inside. Then, as a result, the anchor surfaces of the insertion pieces are disengaged from the respective anchor-holding surfaces formed on the socket. As the user pulls out the plug from the socket, the former comes out from the latter.

[0008] In the above described conventional buckle, the apertures of the socket through which the operating sections of the plug are exposed to the outside are formed by obliquely cutting out the front and rear walls from the lateral walls of the periphery of the socket so that consequently the apertures of the lateral walls are made very large.

[0009] As a result, when the user depresses the operating sections of the plug exposed to the outside through the apertures of the socket by means of the thumb and one of the fingers, they go unnecessarily deep into the inside of the socket through the respective apertures to resiliently deform the insertion pieces of the plug to an unnecessary large extent.

[0010] Then, the insertion pieces of the plug can be damaged (broken) to undesirably reduce the service life of the buckle.

SUMMARY OF THE INVENTION

[0011] Therefore, it is a principal object of the present invention to provide a buckle that dissolves the problems of damaged insertion piece and reduced service life.

[0012] According to the invention, the above object is achieved by providing a buckle comprising a male member and a female member for receiving and anchoring the male member; the male member having a male member main body, a resiliently deformable insertion piece formed on the male member main body, an anchor surface formed on the insertion piece and an operating section also formed on the insertion piece and adapted to resiliently deform the insertion piece; the female member having a female member main body, an insertion hole formed in the female member main body and adapted to receive the insertion piece of the male member inserted into it, anchor-holding surface formed on the female member main body to be engaged with the anchor surface of the male member so as to hold the male member in the female member and an aperture adapted to expose the operating section of the male member to the outside as the anchor-holding surface is engaged with the anchor surface; the aperture being formed by inwardly cutting out the front and rear walls of the periphery of the female member main body having the insertion hole from the lateral wall of the main body and provided at peripheral edge thereof with projecting section projecting toward the aperture.

[0013] With the above described arrangement to anchor the male member to the female member, the user inserts the insertion piece of the male member into the insertion hole of the female member. Then, the anchor surface of the insertion piece is held to the anchor-holding surface of the female member and the male member is anchored to the female member.

[0014] To release the male member that has been inserted into and anchored to the female member from the latter, the user depresses the operating section of the male member exposed to the outside through the aperture of the female member to disengage the engaged state of the male member and the female member. Since the aperture of the female member is provided with projecting section, the thumb and the finger of the user depressing the operating section abut the projecting section and therefore cannot go deep into the inside of the female member through the aperture. Thus, the problems of damaged insertion piece and reduced service life are dissolved. In other words, since the insertion piece of the male member is not resiliently deformed to an unnecessary extent it is scarcely damaged and the service life of the buckle is prolonged.

[0015] Preferably, the projecting section is formed at the edge of the aperture located remote from the inlet aperture of the insertion hole so as to project toward the inlet aperture of the insertion hole.

[0016] With this arrangement, the projecting section project toward the edge of the aperture located close to the inlet aperture of the insertion hole from the edge of the aperture remote from the inlet aperture of the insertion hole. The anchor-holding surface of a buckle according to the invention is mostly arranged at the edge of the aperture located close to the inlet aperture. Therefore, the projecting section projects toward the anchor-holding surface located close to the inlet aperture of the insertion hole. Thus, when the user depresses the operating section of the male member by the thumb and one of the fingers to release the male member from the female member, the position of the front end of the thumb and that of the front end of the finger are forced to come close to the anchor-holding surface so that the operating section is depressed by the thumb pad and the finger pad at position located close to the anchor-holding surface of the operating section. Then, the male member can be released from the female member if the operating section is depressed by the thumb and the finger only to a small extent.

[0017] Preferably, in a buckle according to the invention, the projecting section projects continuously from the position of the edge of the cut out area of the front and rear walls located remotest from the inlet aperture of the insertion hole and the transversal dimension of the projecting section is gradually reduced toward the inlet aperture of the insertion hole.

[0018] The transversal dimension of the projecting section as used herein refers to the dimension thereof as observed in a direction intersecting the direction along which the projecting section projects (opposite to the direction along which the male member of the buckle is inserted). The expression that the transversal dimension of the projecting section is gradually reduced toward the inlet aperture of the insertion hole as used herein may refer to a state where the projecting section is tapered toward the inlet aperture or a state where the projecting section is pointed.

[0019] With such an arrangement, if the thumb and the finger depressing the operating section abut the projecting section, they will not be pressed hard intensively at a point because the projecting section is continuously formed from the edge of the cut out area of the front and rear walls of the female member to the lateral wall. Additionally, since the projecting section is continuously tapered, it shows a sufficient strength and hence is prevented from being damaged.

[0020] Preferably, in a buckle according to the invention, the projecting section is formed to show a curved profile continuously from the edge of the cut out area of the front and rear walls of the female member to the lateral walls.

[0021] With such an arrangement, since the projecting section is formed to show a curved profile continuously from the edge of the cut out area of the front and rear walls of the female member to the lateral wall, if the thumb and the finger depressing the operating section abut the corresponding projecting section, they will not be pressed hard intensively at a point Additionally, since the projecting section shows a curved profile, it is not likely to be damaged.

[0022] For the purpose of the invention, in a state where the male member is anchored to the female member, the anchored state can be dissolved by depressing the operating section of the male member that is exposed to the outside from the aperture of the female member and the projecting front end of the projecting section may be located closer to the inlet aperture of the insertion hole than the front ends of the insertion piece anchored to the inside of the insertion hole.

[0023] For the purpose of the invention, preferably, the male member has a pair of insertion pieces projecting respectively along the lateral edges of the male body in parallel with each other and the anchor surfaces and the operating sections are arranged respectively on the on the surfaces opposite to the mutually opposing sides the corresponding insertion pieces, whereas the anchor-holding surfaces and the apertures are formed respectively at the oppositely disposed lateral walls of the insertion hole of the female member main body of the female member.

[0024] With this arrangement, since the male member has a pair of insertion pieces, on the surfaces opposite to the mutually opposing sides of which the anchor surfaces and the operating sections are arranged respectively, the anchor surfaces formed respectively at the front ends of the paired insertion pieces are held to the corresponding anchor-holding surfaces of the female member when the male member is inserted into the female member. Thus, the male member can be anchored reliably to the female member. Additionally, the male member can be released easily from the female member because only the operating sections formed on the outer sides of the paired insertion pieces need to be depressed inwardly to release the male member from the female member.

[0025] For the purpose of the invention, preferably, the male member and the female member are made of synthetic resin as integral entities.

[0026] With this arrangement, being made of synthetic resin as integral entities, the male member and the female member can be manufactured at low cost on a mass production basis.

[0027] For the purpose of the invention, preferably, the male member and the female member are provided respectively with strap fitting slots, through which the corresponding ends of the strap member are passed and to which they are anchored.

[0028] With this arrangement, since the male member and the female member are provided respectively with strap fitting slots, the male member and the female member can be easily and securely linked to the strap member simply by passing the strap member through the strap fitting slots. Thus, a buckle according to the invention is easy to use.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029]FIG. 1 is a schematic perspective view of an embodiment of buckle according to the invention;

[0030]FIG. 2 is a perspective view of the male member and the female member of the embodiment of FIG. 1 that are released from each other;

[0031]FIG. 3 is a schematic cross sectional view of the male member and the female member of the embodiment of FIG. 1 that are anchored to each other;

[0032]FIG. 4 is a schematic cross sectional partial view of the embodiment of FIG. 1, illustrating how the male member and the female member that have been anchored to each other are released from each other,

[0033]FIG. 5 is a schematic cross sectional partial view of one of the apertures obtained by modifying the profile of those of the embodiment; and

[0034]FIG. 6 is a schematic cross sectional view of a buckle obtained by modifying the embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0035] Now, the present invention will be described by referring to the accompanying drawings that schematically illustrate a preferred embodiment of the invention.

[0036]FIGS. 1 through 4 illustrate this embodiment of buckle according to the invention. As shown in FIG. 1, the embodiment of buckle 1 is adapted to connect and disconnect the ends 2, 3 of a strap member and comprises a male member 10 made of synthetic resin as integral entity and a female member 20, which the male member 10 is inserted into and held, also made of synthetic resin as integral entity. Incidentally, the material used for forming the male member 10 and the female member 20 is not limited to synthetic resin, it can alternatively be metal or some other appropriate material.

[0037] As also shown in FIGS. 2 and 3, the male member 10 has a male member main body 11, a pair of insertion pieces 15 projecting respectively from the lateral sides of the male member main body 11 in parallel with each other so as to be resiliently deformable, and a guide piece 19 projecting between and in parallel with the insertion pieces 15.

[0038] The male member main body 11 is provided at a middle section thereof with a strap fitting slot 12, through which the corresponding end 2 of the strap member is passed and to which it is anchored, and at the lateral sides thereof with a pair of abutting sections 14 to which the connecting surface 20A of the female member 20 abuts. The strap fitting slot 12 is further divided into two strap fitting apertures 12A, 12B by a link beam 13, which is interposed in the strap fitting slot 12, to regulate the effective length of the strap member.

[0039] The insertion piece 15 is composed of a pair of thin and resilient arm sections 15A integrally formed with and extending from the lateral sides of the respective male member main body 11 and a pair of bulged sections 15B extending respectively from the front ends of the resilient arm sections 15A. Each of the bulged sections 15B has an insertion guide surface 16 that is outwardly rounded from an inner position of the base end toward the front end thereof, an operating section 17 that is a mildly outwardly curved surface extended from the front end of the insertion guide surface 16, and an anchor surface 18 extending inwardly from the operating section 17 substantially at a right or acute angle, the insertion guide surface 16, the operating section 17 and the anchor surface 18 being arranged in the mentioned order.

[0040] The guide piece 19 is formed in such a way that its thickness is gradually reduced as it extends from the male member main body 11 toward a middle section thereof and then increased as it extends further from the middle section toward the front end thereof. A rectangular hollow section 19A is formed in the guide piece 19 from the rear surface thereof to reduce the volume of the material consumed for the buckle.

[0041] As also shown in FIGS. 2 and 3, the female member 20 has a female member main body 21.

[0042] The female member main body 21 is provided with a strap fitting slot 22, through which the corresponding end 3 of the strap member is inserted and to which it is anchored, and an insertion hole 23 running all the way from the connecting surface 20A of the female member 20 to be connected to the male member 10 to the strap fitting slot 22, into which the insertion pieces 15 and the guide piece 19 of the male member are inserted. The connecting surface 20A of the female member 20 (to be connected to the male member 10) shows an inwardly curved profile that is recessed most at the center.

[0043] The oppositely disposed lateral walls of the insertion hole 23 extending from the inlet aperture of the latter are gradually inwardly inclined toward the remote end of the hole so that, when the insertion pieces are inserted into the insertion hole 23, each of them operates as abutting section 24 that abuts the insertion guide surface 16 of the corresponding insertion piece 15 and resiliently deforms the piece 15 in a direction substantially perpendicular to the inserting direction of the insertion piece 15. Apertures 25 that expose the respective operating sections 17 of the male member 10 are formed through the lateral walls of the insertion hole 23 in areas located beyond the respective abutting sections 24 as viewed from the insertion hole 23.

[0044] The apertures 25 are produced by partly and inwardly cutting out the front and rear walls 21B, 21C of the periphery of the female member main body 21 having the insertion hole 23 from the lateral walls 21A. To be more specific, each of the apertures 25 is produced by inwardly cutting out the front and rear walls 21B, 21C from the aperture edges 25A, 25B of the corresponding lateral wall to show an inwardly curved profile. The aperture edge 25A that is located closer to the insertion hole 23 than the other aperture edge 25B is provided with an anchor-holding surface 27 that comes to be engaged with the anchor surface 18 of the corresponding insertion piece 15 to anchor the male member 10 to the female member 20, whereas the aperture edge 25B that is located remote from the inlet aperture of the insertion hole 23 is provided with a projecting section 28 that projects toward the aperture of the lateral wall.

[0045] The projecting section 28 has a curved surface defined by lines extending from the edges 25C of the cut out parts of the front and rear walls 21B, 21C and connected to the lateral wall 21A. To be more specific, the projecting section 28 projects toward the aperture edge 25A of the corresponding lateral wall as the defining lines are extended from the edges 25C of the cut out parts of the front and rear walls 21B, 21C and its curved surface is mildly connected to the lateral wall 21A. The transversal dimension of the projecting section 28 is large at the base section thereof (at the position indicated by the dotted broken line defining the lower end of L1 in FIG. 3) and small at the front end section thereof (at the position indicated by the dotted broken line defining the upper end of L1 in FIG. 3). In other words, the projecting section 28 is tapered toward the front end thereof.

[0046] The height of the projecting section 28 (as indicated by L1 in FIG. 3), which is the distance L1 from the deepest position of the edges 25C of the cut out parts of the front and rear walls 21B, 21C to the front end of the projecting section 28, is so selected that the thumb or finger depressing the corresponding operating section 17 is not caught by the gap between the projecting section 28 and the insertion guide surface 16 and the operating section 17 of the insertion piece 15.

[0047] Note that, in a state where the male member 10 is inserted into and anchored to the female member 20, the outermost surface of each of the operating sections 17 is located inside the contour line connecting the separated parts of the corresponding lateral wall 21A of the female member main body 21.

[0048] The above described embodiment operates in a manner as described below. To anchor the male member 10 to the female member 20, the user inserts the insertion pieces 15 of the male member 10 into the insertion hole 23 of the female member 20. Then, the insertion guide surfaces 16 formed at the front ends of the insertion pieces 15 abut the respective abutting sections 24 of the female member 20 so that the insertion pieces 15 are inserted further as they are resiliently deformed in respective directions (inwardly) that are substantially perpendicular to the inserting direction of the insertion pieces 15. As the anchor surfaces 18 of the insertion pieces 15 pass by the respective anchor-holding surfaces 27 of the female member 20, the resiliently deformed insertion pieces 15 restore the original state so that the anchor surfaces 18 of the insertion pieces 15 are retained by the respective anchor-holding surfaces 27 of the female member 20. As a result, the male member 10 is anchored to the female member 20.

[0049] To release the male member 10 from the female member 20, the user inwardly depresses the operating sections 17 formed at the front ends of the respective insertion pieces 15 and projecting from the respective apertures 25 of the female member 20, and by doing so, the insertion pieces 15 of the male member 10 are inwardly and resiliently deformed and hence the anchor surfaces 18 are released from the respective anchor-holding surfaces 27. In this state, the connection between the male member 10 and the female member 20 can be disconnected by pulling out the male member 10 from the female member 20.

[0050] At this time, as the operating sections 17 of the male member 10 are depressed inwardly, the depressing thumb and finger of the user abut the projecting sections 28 so that they cannot go deep into the female member 20 through the apertures 25. Therefore, the insertion pieces 15 of the male member 10 are not deformed beyond the necessary level. In other words, the insertion pieces 15 are not damaged and broken unnecessarily so that service life thereof is prolonged.

[0051] Additionally, since the thumb and finger of the user for depressing the operating sections 17 abut the respective projecting sections 28 and therefore cannot go deep into the female member through the apertures 25, neither the thumb nor the finger would be pinched between the operating sections 17 of the male member 10 and the edges of the corresponding apertures 25 of the female member 20. If the user temporarily removes or reduces the pressure he or she is applying to the operating sections 17 of the insertion pieces 15 in an operation of, for example, releasing the male member 10 from the female member 20, the insertion pieces 15 tend to restore the respective outer positions by resiliency. If the insertion pieces 15 actually restore the respective outer positions by resiliency, neither the thumb nor the finger of the user that are depressing the operating members 17 of the male member 10 would be pinched between the operating sections 17 and the edges of the corresponding apertures 25 of the female member 20 because they do not go deep into the female member 20 through the apertures 25 due to the provision of the projecting sections 28.

[0052] The above described embodiment can provide the following advantages.

[0053] (1) Since the apertures 25 of the female member 20 are produced by partly and inwardly cutting out the front and rear walls 21B, 21C of the periphery of the male member main body 21 with the insertion hole 23 formed therein, and the projecting sections 28 that project toward the apertures of the lateral walls is provided in the vicinity of the aperture edges 25B, the thumb and finger, which depress the operating sections 17 of the male member 10 to release the male member 10 from the female member 20, abut the projecting sections 28 and therefore cannot go deep into the female member 20 through the apertures 25. In other words, the insertion pieces 15 of the male member 10 are not deformed beyond the necessary level so that the insertion pieces 15 are not damaged and broken unnecessarily and hence service life thereof is prolonged.

[0054] (2) Since the thumb and finger of the user for depressing the operating sections 17 cannot go deep into the female member through the apertures 25, neither the thumb nor the finger would be pinched between the operating sections 17 of the male member 10 and the edges of the corresponding apertures 25 of the female member 20. If the user temporarily removes or reduces the pressure he or she is applying to the operating sections 17 of the insertion pieces 15 in an operation of releasing the male member 10 from the female member 20, the insertion pieces 15 tend to restore the respective outer positions by resiliency, neither the thumb nor the finger of the user that are depressing the operating members 17 of the male member 10 would be pinched between the operating sections 17 and the edges of the corresponding apertures 25 of the female member 20 because they do not go deep into the female member 20 through the apertures 25 due to the provision of the projecting sections 28.

[0055] (3) The projecting sections 28 have a curved surface defined by lines extending from the edges 25C of the cut out parts of the front and rear walls 21B, 21C and connected to the respective lateral walls 21A. Therefore, when the projecting sections 28 are pushed by the thumb and one of the fingers of the user, they are not pressed intensively at a spot. Additionally, since they have a curved surface, the projecting sections 28 are prevented from being damaged.

[0056] (4) The aperture edges 25A that are located closer to the insertion hole 23 than the other aperture edges 25B are provided with respective anchor-holding surfaces 27, whereas the aperture edges 25B that are located remote from the inlet aperture of the insertion hole 23 are provided with respective projecting sections 28 that project toward the apertures of the respective lateral walls. Therefore, when the user depresses the operating sections 17 of the male member 10 by the thumb and one of the fingers to release the male member 10 from the female member 20, he or she uses the thumb pad and the finger pad and depresses the operating sections 17 at positions close to the respective anchor-holding surfaces 27. Then, the male member 10 is released from the female member 20 if the operating sections 17 are depressed only to a small extent.

[0057] (5) Since the male member 10 is provided with a pair of insertion pieces 15 arranged at respective lateral extreme positions, each having an anchor surface 18 and an operating section 17, the anchor surfaces 18 formed on the pair of insertion pieces 15 hold the respective anchor-holding surfaces 27 of the female member 20 when the male member 10 is fully inserted into the female member 20, thus the male member 10 is reliably anchored to the female member 20. To release the male member 10 from the female member 20, it is only necessary to inwardly depress the operating sections 17 arranged on the outer lateral surfaces of the paired insertion pieces 15 and hence the male member 10 can be easily released from the female member 20.

[0058] (6) Since the male member 10 and the female member 20 are made of synthetic resin as integral entities, they can be manufactured at low cost on a mass production basis.

[0059] (7) The male member 10 and the female member 20 are provided respectively with the strap fitting slots 12, 22, through which the corresponding ends 2 of the strap member are passed and to which they are anchored. Therefore, the male member 10 and the female member 20 can be easily and securely linked to the strap member simply by passing the strap member through the strap fitting slots 12,22. In short, the embodiment is easy to use.

[0060] (8) The outermost lateral surface of each of the operating sections 17 is located inside the contour line connecting the two separated parts of the corresponding lateral wall 21A of the female member main body 21, in other words, the operating sections 17 of the male member 10 are not projecting from the outer surface of the female member main body 21, therefore, the strap or the belt would not be caught by the operating sections 17.

[0061] The present invention is by no means limited to the above described embodiment of buckle, which may be modified in various different ways including the following modifications.

[0062] While the apertures 25 of the female member 20 of the above described embodiment are produced by partly and inwardly cutting out the front and rear walls 21B, 21C from the aperture edges 25A, 25B of the respective lateral walls to show an inwardly curved profile, the profile of the apertures 25 is not limited thereto and may alternatively have a different profile. For example, they may have a rhombic profile having two linear sides that are in parallel with each other and fall inwardly and downwardly (toward the strap fitting slot 22 of the female member 20) from the aperture edges 25A, 25B of the respective lateral walls as shown in FIG. 5. With this arrangement, the projecting sections 28 are formed at the aperture edges 25B of the lateral walls simultaneously when the apertures 25 having a rhombic profile are formed.

[0063] While it is sufficient that the projecting sections 28 have a height L1 that does not allow the thumb and one of the fingers of the user depressing the operating sections 17 to enter the respective gaps between the projecting sections 28 and the insertion guide surfaces 16 and the operating sections 17 of the corresponding insertion pieces 15, it is desirable that the height L1 is determined corresponding to the distance L2 between the aperture edges 25A, 25B of each of the apertures 25 as shown in FIG. 5. More specifically, it is desirable to select a value for the height L1 corresponding to the value for distance L2, which is set corresponding to the size of the thumb or the fingers of the user for letting the thumb and one of the fingers depressing the projecting sections 28 touch (bridge) the aperture edges 25A, 25B of the respective lateral walls.

[0064] While the insertion guide surfaces 16 are formed at the front ends of the respective insertion pieces 15 of the above described embodiment, they may alternatively be formed at middle positions of the insertion pieces 15 instead of the front ends.

[0065] While the anchor-holding surfaces 27 are formed at the aperture edges 25A of the lateral walls of the apertures 25 in the above described embodiment, the positions of the anchor-holding surfaces 27 are not limited thereto. They may alternatively be formed at positions separated from the apertures 25.

[0066] While the above described embodiment is provided with a pair of insertion pieces 15, it may alternatively be provided with a single insertion piece 15 or more than two insertion pieces 15.

[0067]FIG. 6 shows a buckle having only a single insertion piece 15. In the illustrated instance, therefore, only a single aperture 25 is formed at a lateral side of the female member 20. With this arrangement, the advantages of (1), (2), (3), (4), (6), (7) and (8) listed above by referring to the embodiment are provided.

[0068] The above described embodiment of buckle can find numerous applications including bags. Particularly, it may find suitable applications where the buckle should not be unfastened when tensile force exceeding a predetermined level is applied thereto.

[0069] While both the male member 10 and the female member 20 of the above described embodiment are formed by molding synthetic resin (injection molding or injection/compression molding), they may alternatively be formed by molding metal and the like. 

What is claimed is:
 1. A buckle comprising a male member and a female member for receiving and anchoring the male member; said male member having a male member main body, a resiliently deformable insertion piece formed on the male member main body, an anchor surface formed on the insertion piece and an operating section also formed on the insertion piece and adapted to resiliently deform the insertion piece; said female member having a female member main body, an insertion hole formed in the female member main body and adapted to receive the corresponding insertion piece of the male member inserted into it, an anchor-holding surface formed on the female member main body to be engaged with the anchor surface of said male member so as to hold the male member in the female member and an aperture adapted to expose the operating section of said male member to the outside as the anchor-holding surface is engaged with the anchor surface; said aperture being formed by inwardly cutting out the front and rear walls of the periphery of the female member main body having said insertion hole from the lateral wall of the main body and provided at peripheral edge thereof with projecting section projecting toward the aperture.
 2. A buckle according to claim 1, wherein said projecting section is formed at the edge of said aperture located remote from the inlet aperture of said insertion hole so as to project toward the inlet aperture of said insertion hole.
 3. A buckle according to claim 2, wherein said projecting section projects continuously from the position of the edge of the cut out area of the front and rear walls located remotest from the inlet aperture of the insertion hole and the transversal dimension of the projecting section is gradually reduced toward the inlet aperture of the insertion hole.
 4. A buckle according to claim 2, wherein said projecting section is formed to show a curved profile continuously from the edge of the cut out area of the front and rear walls of the female member to the lateral wall.
 5. A buckle according to claim 2, wherein the state where the male member is anchored to the female member can be dissolved by depressing the operating section of the male member that is exposed to the outside from the aperture of the female member; and the projecting front end of said projecting section are located closer to the inlet aperture of the insertion hole than the front end of the insertion piece anchored to the inside of the insertion hole.
 6. A buckle according to claim 1, wherein said male member has a pair of insertion pieces projecting respectively along the lateral edges of the male body main body in parallel with each other and said anchor surfaces and said operating sections are arranged respectively on the surfaces opposite to the mutually opposing sides of the corresponding insertion pieces, whereas said anchor-holding surfaces and said apertures are formed respectively at the oppositely disposed lateral walls of the insertion hole of the female member.
 7. A buckle according to claim 1, wherein said male member and said female member are made of synthetic resin as integral entities.
 8. A buckle according to claim 1, wherein said male member and said female member are provided respectively with strap fitting slots, through which the corresponding ends of the strap member are passed and to which they are anchored. 